There are known childproof safety capsules comprising a cap for closing a container and a cover that surmounts said cap.
An axial direction identified by the direction of extension of the neck of the container is defined. For the purpose of enabling the capsule to be opened, the cover must be pushed along this axial direction (so as to mesh said cover and said cap), while also turning the cover in a first direction at the same time (in fact, it has been demonstrated that the coordinated combination of these two movements proves to be particularly difficult for children under the age of 6 years). This prevents children from accidentally gaining access to the contents of the container. Similar applications are typically used for containers designed to contain pharmaceutical products. In safety capsules, the cover serves the function of preventing an outside user from gaining direct access to the cap. This cover further comprises an annular projection that projects towards the cap and engages below an annular abutment afforded in the cap. This prevents the cover from being removed when the latter is being pulled along said axial direction and thus prevents access to the underlying cap. To enable the capsule to be screwed back on the container, the outer cover comprises a projection that projects inwardly and that can interact with a protrusion that projects outwardly from the cap. In a plane perpendicular to an axis of cylindrical symmetry of the container, a section of this protrusion is shaped in the form of a right-angled triangle. When the cover turns in a direction for tightening the capsule, the projection intercepts a leg of this right-angled triangle, enabling transmission of motion from the cover to the cap and thus closure on the container. When the cover turns in a direction opposite the tightening direction (corresponding to the direction for opening the container), said projection intercepts the hypotenuse of the above-mentioned right-angled triangle, which therefore, owing to its inclination, constitutes a guide for the cover to slide freely with respect to the cap (as described above for enabling the opening thereof, in addition to turning the cover, axial pushing of the cover towards the cap is in fact needed to enable meshing of the cap and cover). One drawback of this solution relates to the fact that sometimes when the capsule is being screwed back on the container, as the protrusion indicated hereinabove (cross-sectionally shaped in the form of a right-angled triangle) interacts with the above-mentioned projection (having a cross section that is less sturdy), it breaks it or forces it to turn over, making it useless. This obviously impairs proper functioning of the capsule.